In manufacturing of a semiconductor device, a circuit pattern is formed by a so-called lithography process that forms a predetermined film on a wafer which is a substrate to be processed, then forms a resist film by coating a resist solution, then exposes the resist film with a pattern corresponding to the circuit pattern, and thereafter develops the exposed resist film. In such a lithography process, the wafer is mainly subjected to process steps including a cleaning step, a dehydrating-baking step, an adhesion (hydrophobizing) step, a resist coating step, a pre-baking step, an exposure step, a developing step and a post-baking step, which are performed in that order, whereby a predetermined fine pattern is formed in the resist film.
Known developing methods includes a so-called puddle (stationary) developing method that develops a wafer while a puddle of a developing liquid is formed on the wafer surface. In the puddle developing method, since the resist film is water-repellent and has high surface tension in general, if the amount of the developing liquid is insufficient, there may occur a pull-back phenomenon in which an aggregation of the developing liquid is pulled into another aggregation of the developing liquid, whereby areas which are not wetted with developing liquid (i.e., non-developed areas) may exist in the wafer surface. Thus, a relatively large amount of developing liquid must be supplied on the wafer surface such that the whole surface of the wafer is covered with the developing liquid, resulting in larger consumption of the developing liquid.
Known developing methods also include a so-called puddle-less (rotating) developing method that rotates a wafer about a vertical axis and moves a developing nozzle from the center toward the periphery of the wafer while the developing nozzle supplies a strip-shaped developing liquid whose width extends in the radial direction of the wafer, whereby the wafer surface is coated with the developing liquid in a spiral form. In this puddle-less developing method, dissolved components of the resist is removed together with the developing liquid spreading radially due to the centrifugal force. Thereafter, a rinse liquid such as deionized water is supplied to the center of the wafer. As a result, the parts of the resist which are not soluble in the developing liquid remain on the wafer, and thus the predetermined resist pattern is obtained (See JP2005-210059A, for example.).
In general, the puddle-less method can reduce the developing time and the resist-liquid consumption as compared with the puddle method.
However, even though the puddle-less method is employed, in some cases, it is still difficult to satisfy both of the process margin (or process performance) and the process economy (i.e., shorter processing time, less developing liquid consumption). Herein, the process margin refers to the difference of an actual value of a parameter for evaluating the result of the process from the allowable limit value of the parameter, where the parameter may be, for example, in-plane uniformity of the CD value, the amount of defects formed due to re-adhesion of components dissolved in the developing liquid.
Specifically, in a case where a substrate, having thereon a resist protection film used in an ArF immersion lithography or having thereon a water-repellent resist film, is developed, such a highly water-repellent surface repels a developing liquid or a rinse liquid, which may result in deteriorated process efficiency of a developing process or a rinse process. Thus, the processing time (developing time) or the amount of the processing liquid must be increased in order to achieve sufficient process performance.